The present invention pertains generally to the synthesis of phosphazene oligomers and polymers and in particular to the alkylation of these oligomers and polymers.
Polyphosphazenes break down to yield small rings at temperatures above 200.degree. C., which is significantly higher than the decomposition temperature of most organic polymers. However, the need for polymers with the flexibility, flame retardation, and the resistance to ultraviolet light of polyphosphazenes in uses at temperatures above 200.degree. C. is great.
Thermal stability, along with glass-transition temperature, degree of crystallinity, and melt behavior, are strongly affected by the pesence of different substituent groups on the backbone chain. One substituent group, which is very promising, is the alkyl group. Previous attempts at alkylating cyclic or acyclic polyphosphazenes resulted in cleavage of the polyphophazene chain.